Handling System for Moulded Parts

The present invention relates to a handling system for moulded parts and more specifically, although not exclusively, to a method and apparatus for conveying an array of parts away from a mould for subsequent packaging thereof.

It is well known within the art to provide some form of conveying means for carrying moulded parts between a mould and a remote station, such as for example, a packing station, an inspection station or the like. In the case of individually injection moulded plastic parts, it may be sufficient to simply open the mould and eject the moulded part such that it falls onto a conveyor belt, which then carries the moulded part away from the mould.

However it is often the case that a single mould includes multiple cavities for the simultaneous generation of multiple parts in a single moulding cycle. The multiple cavities are typically connected to a common feed channel or sprue by a series of ducts so that the melt can be injected into multiple cavities at once. This results in the moulded parts being connected by a tree of material, often referred to as a runner, formed by the material in the ducts joining the individual cavities to the sprue during moulding. Thus when the mould is opened, a single conjoined mass of parts is ejected, rather than a series of individual parts.

When removing the parts from the mould, the runner provides a useful common formation, by which the multiple parts can be handled. However the individual parts must then be separated from the runner for subsequent inspection, counting and/or packaging steps to be carried out. The separation of the individual parts is typically achieved by cutting. For high volume, low cost parts, such as, for example, cable ties and the like, the cut cable ties are allowed to fall onto a conveyor belt or chute and transported to the next station.

However the exact manner in which the individual parts may fall is unknown and varies between each different array of parts due to minute variables in cutting parameters, material thicknesses and orientation of the parts in the array. Thus the exact final resting positions of individual parts on the conveyor belt is almost impossible to predict. This

random orientation of parts on the conveyor belt causes significant problems when attempting to inspect, count and/or collate parts for packaging downstream of the cutting station.

For high cost, low volume parts, the additional expense of correctly redistributing the parts for subsequent operations may be justified. However, for low cost, high volume parts, such as cable ties, the manipulation of every part into a predefined orientation and spacing is uneconomic in view of the required throughput of a production line.

Whilst the following description proceeds specifically in relation to elongate moulded plastic parts, such as cable ties, it will be appreciated that many other types of parts are manufactured by moulding and are therefore prone to similar problems associated with the conveying of the part away from the mould. It is intended that the present invention encompasses any such parts.

One commonly adopted solution is to manually handle the cable ties for inspection and counting into packages. This manual operation is costly and can cause a bottleneck in a production line. The alternative is to bundle the cable ties into packages without stringent inspection or counting, such that the number of parts in each package is subject to variation. This has a detrimental effect on the end user's perception of the product quality due to the inability to tightly control the output of the production line.

Furthermore, the small width dimension of cable ties makes ties difficult to handle using automated means. When combined with the unpredictable nature in which cable ties fall, this causes problems when attempting to automate handling of cable ties in a reliable manner.

It is an object of the present invention to provide automated conveying and packaging systems for moulded parts, in which the parts are manipulated with improved predictability.

According to a first aspect of the present invention, there is provided conveying means for carrying an array of moulded parts from a mould, the conveying apparatus being movable to and from a position adjacent the mould and comprising: retaining means

comprising a plurality of retaining formations arranged in an array corresponding to the array of parts within the mould, wherein each of said formations is arranged to releasably retain a corresponding moulded part in said array upon ejection from said mould; and, guide means for guiding each part into a corresponding retaining formation, said guide means arranged to be interposed between said retaining formations and said mould when the conveying means is in said position adjacent the mould.

The present invention is particularly advantageous in that each part ejected from the mould is constrained by the guide means as it moves to a predetermined retained position in the conveying means. Thus the relative orientation of the parts in the array is preserved during movement from the mould to the conveying means and the parts are then resiliently held in place by the retaining means during transit. Conversely, when the parts are released from the retaining means, the guide means preserves the orientation of the array of parts up to the point of exit from the conveying means. When the conveying means is placed adjacent a flat surface, such as a conveyor belt, the parts are reliably laid down in said predetermined array.

Typically the parts are elongate in shape and the retaining means is arranged to hold each part part-way along its length. Preferably the retaining means applies a retaining force laterally across each part. Thus the entire length of the parts do not need to be enclosed, but instead the parts can be gripped at a predetermined position such that the remainder of the part is unconstrained. This minimizes contact with the part whilst it is still warm.

The retaining means and/or guide means may comprise one or more walls. The or each wall may be shaped so as to have one or more slots therein for reception of a part. The retaining means may comprise first and second retaining members arranged to allow relative movement therebetween so as to trap each part between said retaining members. The first and second retaining members may comprise retaining formations of different shapes. Either retaining member may comprise a locking portion which extends substantially laterally to the guide means.

In one embodiment, the conveying means further comprises support means movable relative to the guide means and retaining formations. Preferably the support means is

movable in a direction substantially parallel to said guide means. The support means may be arranged to oppose the ejection of the parts from the mould in a resilient manner. In this regard, the parts are typically ejected from the mould using ejection means such as ejector pins and the support means resists or buffers the movement of the part away from the mould so as to control the movement of the part along the corresponding guide.

Thus pressure is maintained on the part as it moves away from the mould to ensure the correct orientation of the part is maintained.

Typically the support means is movable in a reverse direction to eject the parts from the conveying means at the required location. Preferably the support means takes the form of one or more plates, which may be shaped by way of indentations or troughs to receive the parts. Typically a unitary support means is provided for movement relative to multiple guide means.

According to a further embodiment, the retaining formations comprises a plurality of apertures, indentations or cut-outs within a retaining member. The apertures are shaped to closely fit each part and comprise an abutment portion or end wall against which the part can be located.

In one embodiment, the retaining means comprises first and second retaining members. The second retaining member may be movable relative to the first member between first and second positions which correspond to respective open and locked conditions. Preferably, the apertures of the first and second members are aligned in the first condition such that each aperture has an open end or side portion. Preferably the retaining formations of the second member overlie the apertures of the first member in the second position so as to trap each part within the corresponding aperture. Thus the first and second members are moved out of alignment or offset in said second condition.

Preferably, the shape of the apertures in the first and second members are different. Preferably the apertures in the second member have a locking face opposing the abutment portion of the apertures in the first member. Thus the part is trapped between

the locking face of the second member and the abutment portion of the first member when the aperture is closed.

According to one embodiment, the guide means is arranged to guide the parts into the conveying means in a first direction, away form the mould. Preferably the second member is movable in a second direction to trap the parts within the conveying means. Yet more preferably, either the first or second member is moveable relative to the other member in said first direction so as to releasably grip the part in its trapped state between the first and second retaining members

A movement of the second member in the first direction is particularly beneficial since it provides a clearance between the second member and the face of the mould such that the conveying means can then move away from the mould without the conveying means damaging the mould due to contact therebetween.

In a preferred embodiment the first and second members are planar in shape in the form of a wall or plate and are arranged in a side by side orientation. A series of apertures are formed in each plate such that a linear movement of one plate relative to the other can trap or release multiple parts within the apertures in unison.

Preferably the guide means comprise a pair of opposing guiding edges in the form of a slot or channel. Typically each retaining means has a corresponding guide means. In one embodiment a series of linear slots are provided in each of the first and second members. The shape of the slots define the guide means and retaining formations arranged to receive the parts. The guide means may have a section of increased dimensions at one end thereof in order to account for engineering tolerances as the parts are ejected from the mould. Thus the guiding edges may be angled or curved away from each other at an open end thereof in order to define a mouth portion. The slots may be tapered.

The conveying means typically has an alignment edge for locating adjacent the mould surface, the guides extending away from the aligning edge in said first direction such that the retaining formations are spaced from the aligning edge.

According to a further aspect of the present invention, there is provided a method of conveying method of collating moulded parts for packaging, comprising: ejecting the moulded parts from the mould into first conveying means; carrying the parts in a predetermined array in said first conveying means from the mould to second conveying means, wherein each part is individually supported within the array by said first conveying means; transferring said array of parts in a predetermined orientation from said first conveying means to second conveying means; conveying said array of parts in said predetermined orientation to collating means via said second conveying means; collating predetermined numbers of parts into discrete bundles; and, orienting the bundles for insertion into packages .

The moulded parts may be elongate in shape and the orienting the bundles for insertion into packages may comprise orienting the parts for insertion in a direction substantially parallel with the elongate parts.

Preferably the parts are collated by allowing the parts to fall under gravity in predetermined numbers into a receptacle. In one embodiment the parts are transferred from the receptacle to the packages via a chute. Typically the parts fall under gravity into the packages from above. The open end of each package is then sealed.

Dropping the parts into bags from above in a lengthways orientation is a particularly reliable method of packaging elongate parts since each part in the bundle is maintained in its orientation by adjacent parts. Furthermore a minimal frontal area of the parts is presented in the direction of travel. The diameter of a chute or the like can be tailored to avoid the possibility of the elongate parts turning out of alignment as they fall.

The predetermined orientation and spacing of the parts on the second conveying means allows automated inspection and/or counting of the parts prior to bagging. Thus the reliability and control of the production line is significantly increased. The second conveying means typically takes the form of a conveyor belt system. In one embodiment the second conveyor means comprises a pair of spaced conveyor belts. A runner or other waste material from the mould may be deposited between the conveyor belts at the time of positioning the parts on the conveyor, without the requirement for a separate removal step in the production line.

The present invention will now be described in further detail below with reference to the accompanying drawings, of which:

Figure 1 shows a three-dimensional view of conveying means according to the present invention;

Figure 2 shows a three-dimensional view of the first retaining means of figure 1 ;

Figure 3 shows a three-dimensional view of the second retaining means of figure 1 ;

Figure 4 shows a side view of the second retaining means;

Figure 5 shows a three-dimensional view of detail of the conveying means of figure 1 ;

Figure 6 shows a part-cut-away three-dimensional view of further detail of the embodiment of figure 5;

Figure 7 shows a side view of retaining means according to a second embodiment of the present invention;

Figure 8 shows a side view of retaining means according to a third embodiment of the present invention;

Figure 9 shows apparatus for conveying and packaging parts according to the present invention;

Figure 10 shows a sectional view of the conveying means in position adjacent the mould;

Figure 11 shows a perspective view of the second conveying means and collation means of figure 9;

Figure 12 shows further detail of the collation means of figure 11; and

Figure 13 shows the packaging machine arranged for use in accordance with the present invention.

Turning firstly to Figure 1 , there is shown conveying means in the form of a gripper unit 10 designed for removing moulded parts from a multi-cavity injection-moulding tool. The present invention is particularly useful for tools in which the cavities are closely spaced together.

Furthermore, the gripper unit 10 is designed for use in conjunction with a moulding tool having a sub-gate feed system. It will be appreciated by those skilled in the art that sub- gate technology requires material to be injected into the mould cavity in the vicinity of the ejector pin bores. Thus, when the mould opens and the ejector pins are actuated, the moulded part and the material in the ejector pin bore is broken away from the gate. When the parts are ejected from the mould, the tree or runner joining the individual parts has a cylindrical projection of moulded material or sprue extending therefrom, resulting from the excess of material within the ejector pin bore during the moulding process.

Conventional gripping systems are unsuitable for handling sub-gate moulded parts, in which the parts are so closely aligned.

The gripper unit 10 shown in Figure 1 generally comprises a base which takes the form of base plate 12, on which are mounted a series of retaining structures 14A to 14D. In this particular embodiment, a total of four retaining structures are mounted in spaced pairs.

Each retaining structure holds a total of twenty cable ties, arranged in four separate groups of five cable ties each. The cable ties 16A are held towards an end thereof by the retaining structure 14A and extend therefrom in a first direction which is substantially perpendicular to the side of the retaining formation 14A. The adjacent retaining structure 14B holds cable ties 16B in an arrangement which is generally parallel to the cable ties 16A. However, the cable ties 16B extend from the structure 14B in the opposite direction to the cable ties 16A. Thus, the pair of retaining structures 14A and 14B form a spine, from which the sets of cable ties 16A and 16B extend outwardly, either side therefrom.

The second pair of retaining structures 14C and 14D are substantially identical to the structures 14A and 14B, but are mounted on base plate 12, spaced from the first structures 14A and 14B. Thus, the complete gripper unit 10 comprises a total of four retaining structures with the ability to hold a total of eighty cable ties in two separate arrays, having forty cable ties in each. However it will be appreciated that varying numbers and arrays of cable ties can be catered for to suit particular mould cavity arrangements.

The base plate 12 is arranged to be attached to a robot arm, as will be described in further detail below, so that the gripper unit 10 can be moved to and from a position adjacent the open mould.

Each of the retaining structures 14 comprise first 18 and second 20 members, which extend across the base plate 12 in a substantially parallel arrangement. The first member is hereinafter referred to as receptor 18, as shown in Figure 2 and the second member is referred to as retaining blade 20, as shown in Figure 3.

Turning now to Figure 2, an end portion of the receptor 18 is shown, which consists of a pair of spaced side walls 22 and 24, which are joined by base 26. Each of the side walls 22 and 24 extends upwardly from the base 26, such that the receptor 18 is generally U- shaped in section, so as to form an elongate channel 28, in which the retaining blade 20 is located for use.

Each of the side walls 22 and 24 are castellated, so as to provide a series of slots 32 in the outermost edges 34 of the receptor, which are separated by tongues 30. The edges 34 are arranged to be located adjacent the open mould cavity, when the gripper unit is aligned for use. The castellations or tongues 30 are spaced to match the cavity pitches of the mould tool, for which the gripper is designed. Thus, when correctly positioned for use, each trough or slot 32 opens opposite a mould cavity.

Each slot 32 is of width dimension slightly larger than the width of the moulded cable ties 16, so as to allow a small clearance either side of the cable tie when inserted into the slot 32. The slots 32 extend part way into each side wall and terminate at an end face 36, against which each cable tie abuts when located in the slot.

The depth of the channel 28 is at least twice the depth of each slot 32, such that the receptor 18 forms a double wall of castellations, which are spaced from the base 26. The slots 32 are formed in four discrete groups of five slots per group, each slot being arranged to receive a single moulded part at a time.

Turning now to Figure 3, the retaining blade 20 is shown, which is an elongate planar member having a bracket 38 at each end thereof. A spacer 40 is attached between the bracket portions 38 of adjacent retaining blades 20, as can be seen in Figure 1. The spacer 40 also provides a point at which the retaining blade 20 can be actuated during use.

The retaining blade 20 is of thickness substantially equal to or less than the width of the channel 28, such that the retaining blade can be seated within the channel during use. In addition, the height of the retaining blade is substantially equal to, or slightly less than the height of channel 28, such that the outermost edge 42 is substantially flush with, or else retracted from, the edge 34 of the receptor 18 when arranged for use.

The retaining blade 20 is castellated and includes a series of slots 44, which are spaced by a series of tongues having the same spacing and depth as the slots 32 of receptor 18.

Turning now to Figure 4, the details of the slots will be described in further detail. Four sets of five slots are provided along the length of the retaining blade 20, as shown in Figure 1. The width of the cable tie 16 is shown as dimension A in Figure 4. It can be seen that the width of each slot 44 is equal to the width A plus a small clearance either side B. Thus, the total width of each slot is equal to A + 2 B.

Each slot 44 has a mouth portion 48, the sides of which are angled outwardly so as to form a lead of increased width for guiding the cable ties into the slot. The mouth portion 48, in conjunction with the parallel sides 50 and 52 of each slot 44, forms a guide means for constraining the movement of the cable tie into and from the slot. It will be appreciated that the mouth portion 48 and the upper section of the parallel sides 50 and 52 are substantially identical to the arrangement of the slots 32 in the receptor side walls.

The lowermost portion 54 of each slot 44 has a cut-out of greater width than the guiding portion, such that the overall slot 44 takes the form of an L-shape when viewed from the side. The additional width dimension D in the lower portion of the slot is at least two- thirds the width of the cable tie (2/3 of A). The additional width D of the cut-out, forms an opposing edge 56 which is spaced from the base 58 of slot 44, at least by the depth E of the cable tie 16. As shown in Figure 4, the opposing edge 56 is in fact spaced by an additional distance F, so as to provide a clearance for the cable tie when located at the base of the slot, such that the total depth of the increased width portion 54 is E + F.

Referring back to Figure 1 , a moveable supporting member is provided between each pair of retaining structures 14A and 14B, or 14C and 14D, and takes the form of stripper plate 60. The stripper plate is moveable back and forth under the control of actuation means 62 in a direction parallel with the length of the slots 44, that is to say in a direction perpendicular with the base plate 12. The actuation means may comprise a pneumatic, hydraulic or solenoid actuator or any other conventional actuation means.

The basic operation of the gripper unit 10 is described as follows:

Firstly, the gripper unit is moved into position, such that the outermost edges 34 of each receptor 18 abut against the open face of the mould. In this position, the slots 32 in the receptor 18 are aligned with the guiding portions of the slots 44. The openings of both sets of slots 32 and 44 are aligned with the mould cavities. The outermost edges 34 of the receptor 18 protrude slightly beyond the aligning edge 42 of the retaining blade 20, such that, when the receptors 18 are pressed against the mould, the retaining blades 20 are spaced from the mould face by a short distance, such as 1 or 2mm.

The receptors 18 are typically made of nylon such that contact between the mould and the receptor does not damage the mould surface.

When the gripper unit 10 is positioned for use against the face of the mould, the stripper plate 60 is in a raised position, such that it is substantially level with the outermost edges 34 of receptor 18. The ejector pins in the mould then eject the moulded parts outwardly of the mould, such that they press against the stripper plate 60. Thus, pressure is applied to one side of the moulded part by the ejector pins and simultaneously on the

opposing side by the stripper plate 60, such that the parts are ejected from the mould in a controlled and supported manner. As the ejector pins continue their ejection stroke, the stripper plate retracts and each part moves along the correspondingly aligned slot formations in the receptor 18 and the retaining blade 20.

At the end of the full ejection stroke, the parts abut against the end face 36 of each slot. Each receptor 18 is resiliently biased towards the mould such that, when the parts are pressed against the end faces 36, the receptor 18 is pushed backward a short distance by, for example, 1 or 2 mm such that it is clear of the mould face. The retaining blade 20 is then slid longitudinally within the channel 28 relative to the receptor 18, a distance D. Thus, the opposing edge 56 of each slot 44 in the retaining blade 20 moves partway across the slots 32 in the receptor 18 and traps a cable tie in each slot between the end face 36 of the receptor and the opposing edge 56 of the retaining blade.

The retaining blade 20 is then retracted a short distance away from the mould surface, such that the opposing edge 56 applies pressure to the part contained within the slot 44. This therefore tightly grips the part between the opposing edge 56 and the end face 36 of the receptor. In addition, this has the benefit that some compliance is built into the unit, so that a greater clearance is achieved between the injection moulding component in its ejected position and the locking portion of the sliding retaining blade, which prevents jamming. This also beneficially provides a clearance between the unit and the mould surface.

However, it will be appreciated that either the receptor 18 or the retaining blade 20 could undergo relative movement in this regard to the same affect. In addition, the other of the receptor 18 or the retaining blade 20 may be sprung-loaded so as to prevent excess pressure being applied to the moulded parts within the slots.

Once the moulded parts are sufficiently gripped, the gripper unit 10 can then be moved to a remote location away from the mould.

Turning now to Figure 5, further details of the gripper unit 10 are shown. In particular, the actuation means 62 for the retaining blade is shown in further detail. The actuation

means 62 acts on the spacer 40, such that a pair of retaining blades 20 can be actuated in unison.

Also shown in Figure 5 is a sprue grip and eject mechanism 64. The sprue 66 is attached to the runner for the array of moulded parts by virtue of the sub-gate moulding process discussed above. The runner extends lengthways along the gap between adjacent retaining structures and is labelled as part 68 in Figure 1.

The sprue gripper mechanism 64 has opposing gripping arms 70, which can be moved together to clamp the sprue 66 therebetween. The sprue gripper mechanism 64 is then moved forward a short distance by actuator 72, so as to ensure that the sprue and runner are correctly detached and separated from the gripped parts 16. Once the sprue and runner 68 have been forcibly moved a short distance away from the gripped part 16, the sprue and runner can be ejected by releasing the sprue 66, such that the combined sprue and runner fall free of the unit 10. Thus the runner 68 is removed, leaving the moulded parts 16 individually supported by the gripper unit 10 in the required alignment.

Also shown in Figure 5 is flexing means 74, which includes a flexing bar 76 attached to the sprue gripper mechanism 64. In some instances, the removal of the parts 16 from the mould in the array as shown, causes the parts to adversely impinge on the moulding machine. The flexing bar 76 is included to alleviate this problem and runs along the length of the receptors 18, spaced a short distance therefrom and located immediately beneath the parts 16. Upon actuation of the sprue gripper mechanism 64, the flexing bar 76 presses against the underside of the part 16 and flexes the parts to allow clearance of the relevant portions of the moulding machine during movement of the unit 10 away from the mould. Whilst in this embodiment the flex bar 76 is attached for movement in unison with the sprue gripper mechanism 64, it will be appreciated that in an alternative embodiment, the flex bar 76 could be separated therefrom and could be actuated by separate actuation means.

Furthermore, in order to ensure correct operation of the gripper unit 10, precision locaters are fitted between the base plate 12 and the receptor 18 in order to ensure accurate alignment with the mould tool cavities. The base plate 12 is machined for optimum stiffness and minimum weight in order to ensure minimal cycle times. As will be

appreciated by a person skilled in the art, the gripper unit 10 is fitted with interfaces for electrical cables and pneumatic ducting (not shown) to allow control and actuation of the relevant moving parts.

Turning now to Figure 6, a close up view of the retaining structure 14 is shown with one half of the retaining structure 14B removed. The cable ties 16 are held in retaining means 14A at a location close to the head 17 of each cable tie 16. Accordingly the heads 17 of the plurality of cable ties within the array lie between the retaining structure 14A and the runner 68.

In figure 6, there is also shown a reflector 77 mounted on the apparatus in a position such that it is located behind the cable tie heads 17. This reflector 77 is in the form of a reflective strip which is used to allow inspection of the cable ties when held in the apparatus 10. This facilitates automatic inspection of the cable ties 16.

A light source can be used to shine light on the cable ties mounted in the gripper apparatus 10. The light reflecting off reflector 77 effectively backlights the cable ties in the vicinity of the head end 17 with the effect that the silhouette of the cable ties is clearly visible for inspection means. Relative movement between the gripper apparatus and inspection unit allows the cable ties to be scanned for inspection whilst retained in the predetermined array. The light source may be mounted on the gripper apparatus or else may be mounted for movement with the vision inspection means, such as a camera or the like.

For cable ties, the correct formation of the head is most important for product quality and accordingly it is not necessary to inspect the entire length of the ties. However it will be appreciated that the entire parts may be inspected using appropriate lighting.

In figure 7, one end portion of an alternative embodiment of retaining structure 200 is shown which is in some ways preferred to the retaining structure 14 shown in figures 1 to 5. The retaining structure comprises a castellated receptor 202 and retaining blade 204. Only the teeth of the retaining blade 204 are visible in figure 7. The general shape of the castellation is similar to the embodiment of figure 2 and 3, save that the tapered mouth

section of each slot is exaggerated to allow for greater tolerance between the gripping apparatus and the mould tool cavities.

In addition, the receptor 202 is formed of a series of receptor elements 202A-202C. These elements are independently attached to the base of the apparatus, typically by bolts 206. The elements are aligned in a linear, end-to-end arrangement such that the combined receptor elements 202A-202C function in a manner similar to that of the single-piece receptor 18 shown in figure 2. However small gaps can be provided between the receptor elements 202A-202C to allow for thermal expansion of the receptor during use. Thus tolerance issues which can occur during use of a single piece receptor are avoided.

Also shown in figure 7 is actuation means in the form of actuator 208. in this embodiment, the actuator 208 is angled to cause a two-dimensional movement of the retaining blade 204 relative to the receptor 202. Thus when the retaining blade 204 is actuated, it moves both in a longitudinal direction relative to the receptor 202 and also in a direction towards or away from the receptor. As shown in figure 7, the retaining blade 204 can move both left to right and downwards in order to lock the cable tie in place. This action is reversed to release the cable tie.

In an alternative embodiment, a pair of opposing retaining blades may be provided as shown in figure 8. A cable tie can be locked within the castellation 210 of the receptor 202 by a pair of retaining blades which are movable in opposing directions. A pair of opposing retaining formations 212 and 214 lock the cable tie securely in place once removed from the mould. This may require separate actuation means for each retaining blade.

It will be understood that features of the embodiments shown in any of figures 6 to 8 may be used in conjunction with the embodiments of figures 1 to 5 individually. All such features are interchangeable with counterparts in alternative embodiments as far as practicably possible.

Turning now to figure 9, there is shown a system-level diagram of a production line for manufacturing and packaging of moulded parts, such as cable ties. The system

generally comprises moulding machine 78, having a mould 80 with a series of cavities therein, to which molten plastic is fed via a heated injection system. A three-axis robot 82 is mounted adjacent the moulding machine and carries the gripper unit 10 for movement between the mould 80 and a conveyor belt system 84. The conveyor belt system 84 feeds the moulded parts to bagging machine 86 via collation means 88, such that the cable ties are suitably collated and oriented for insertion into bags. The filled bags are inserted into containers provided by the container feed system 90.

The robot 82 has a vertical arm or track 92 and a horizontal arm or track 94, so as to allow two-dimensional movement of the gripper unit 10 in the Y-Z plane. In addition, the robot 82 can rotate the gripper unit 10 about an axis parallel to the Z axis.

After each moulding cycle, the mould 80 is opened and the robot 82 moves the gripper unit 10 into position above the mould 80. The gripper unit 10 is then rotated into a vertical orientation and lowered to a position adjacent the open mould surface.

Figure 10 shows a sectional view of the moulding machine 78 with the gripper unit 10' in place, adjacent the mould face 81. The mould tool 80 is in an open position such that one part of the mould 8OB is spaced from the opposing part of the mould 8OA. In this regard the movable part of the mould 8OB can move to and from the mould part 8OA on shafts 96 in a conventional manner to selectively open and close the mould 80.

In figure 10, the gripper unit 10' has a single pair of retaining structures 14 as opposed to the unit 10 of figure 1 which has two pairs of retaining structures. The aligning edge of each retaining structure 14 is immediately adjacent the mould face 81 for reception of the moulded parts. The robot 82 can move the gripper 10' in the x-direction of figure 9 to achieve correct alignment. In this embodiment the gripper unit 10' is aligned with the moving half 8OB of the mould 80.

The moulded components are ejected into the castellated receptors 18 and retaining blades 20, which pushes the stripper plate 60 away from the mould, the robot then signals the blades 20 to move across into the grip position. The sprue grips 64 are activated if fitted and the moulding machine ejector pins signalled to return. The 3-axis robot 82 then moves the gripper unit away from the mould tool face 81 and clear ready

for vertical movement. If the flex unit 74 is fitted, this is now actuated to bend the moulded components clear of any obstructing machine parts. The 3-axis robot 82 then moves the gripper vertically up to a mould clear position and the flex bar 76 is deactivated.

The 3-axis robot then rotates the gripper unit 10' through substantially 90° so that the components are lying parallel to the floor. The 3 axis robot then moves the gripper to a drop position where it is vertically spaced from the conveyor belt system 84 by approximately 20mm.

Whilst the cable ties in figure 1 are shown as being gripped part-way along their length, adjacent the head end of the ties, it will be appreciated that the gripper unit 10 may be adapted to suit other forms of moulded parts or else to grip the cable ties at an alternative location.

The embodiment described above also has the benefit of allowing a single actuation means to control the gripping of multiple moulded parts at once. It will be appreciated that other forms of retaining means may be provided in place of the sliding blade arrangement, such as, for example suckers.

The conveyor belt system 84 is shown in further detail in figure 11 and comprises a pair of conveyor belts 98 and 99 mounted in a horizontally spaced relationship on a support frame 100. The belts form a pair of continuous loops mounted on rotating shafts and driven by drive means 102 under the control of control means (not shown). Each belt is of width at least equal to the length of the moulded parts and the upper surface of each belt lies in a common plane which is typically horizontal.

The belts are spaced by brackets 104 which define an elongate opening to chute 106 leading to granulator apparatus (not shown).

At one end of the belts 98 and 99 is mounted collation means 88 in the form of a pair of collectors 108 and 110 and a receptacle 112. The receptacle 112 has an opening 114 to allow insertion of moulded parts from above and an open end 116 for emptying of the

receptacle. The collectors'! 08 and 110 are mounted in a fixed position on frame 100, whereas the receptacle is pivotally mounted on a runner 118.

The runner 118 can move linearly along track 120 between three predetermined positions, which are: below the collector 108; below the collector 110; and, above the bagging machine inlet 122 (see figure 13). The receptacle is shown in a horizontal alignment but is allowed to tilt about pivot 119 under control of actuation means so that the opening 116 is selectively angled downwards.

The collector 108 is shown in further detail in figure 12 and has four generally perpendicular side walls 123, an open top and a pair of hinged doors 124 mounted at the lower edge of the side walls 123. The doors are passively hinged at 126 and connected to actuators 128 at the other end thereof. The doors are maintained in a closed position as shown in figure 12 so that the collector forms an open-topped container and are openable momentarily upon operation of the actuators 128.

The movement of the receptacle 112 and the opening of collector 124 is powered by conventional electrical or pneumatic means as will be understood by the skilled person.

During operation, the gripper unit 10 is moved to a position above the conveyor belts 98 and 99, such that the runner 68 is aligned above the opening to chute 106. If fitted, the sprue grip/flex bars are then actuated so as to move the runner system 68 clear of the components. The sprue grips 70 are then released and the runner system 68 falls between the two in-feed conveyors on the collation unit down chute 106 into a granulator. The sprue grip/flex cylinders are then de activated.

The 3 axis robot 82 then lowers the gripper 10 just clear of the conveyors 98 and 99 and signals the blade actuation to move retaining blade 20 to its release position, wherein the slots 32 are aligned with slots 44. At the same time the gripper stripper plate 60 is actuated and the components 16 are pushed onto the two conveyors 98 and 99 in a controlled manner. Since one set of moulded components 16a are arranged in an opposing orientation to the adjacent components 16b, the adjacent arrays of components are positioned in a parallel alignment on the adjacent conveyors, oriented substantially perpendicular to the direction of travel of the conveyor.

If more than one deposit position is required for the mould cavity configuration the robot moves to a second deposit position and repeats the sprue and component ejection sequence. The robot 82 then returns the gripper unit 10 to moulding machine 78 to retrieve the next set of components.

The components on the conveyors are now lying in 2 rows ready to be collated into quantities required for bagging. The conveyors 98 and 99 are sequenced from six-axis robot 130 of the container feed system 90 so as to move the conveyors via an inverter controller at a speed so that the correct quantity of components is deposited in each collector 108, 110.

Inspection means, such as scanners, may be located above the conveyors to determine the dimensions of the components on the conveyors as they pass by. Thus, abnormal components can be detected prior to bagging.

High speed photo-electric sensors may be fitted to count individual components for more precise control if required. Alternatively, the number of components being deposited in the collectors 108 and 110 can be determined by controlling the travel of the conveyors 98 and 99. This is made possible by prior knowledge of the spacing of the arrays of parts on the conveyors. In either embodiment, it will be appreciated that the conveyor belts are driven intermittently so as to control the numbers of parts falling into the collectors. Thus parts can be collated in fractions of each array, multiples of each array or even down to individual parts.

A laser sensor is fitted to ensure that conveyors are clear of all components prior to the next deposition of parts by the 3 axis robot on its next cycle. Half the required bag quantity is metered into each collector 108, 110. When the required quantity is in each collector the conveyors are stopped. Multiple robot cycles may be required to achieve the correct bag quantity.

The collection receptacle 112 is driven to a position below each collector in turn, at which time the doors 124 are opened to allow the collated components to fall into the receptacle 112. The collection receptacle 112 now has the correct quantity of

components required for each bag and moves into position above the bagging machine inlet 122 and rotates, tipping all the components out into the bagging machine 86.

The bagging machine 86 is of the vertical form and fill variety, which will be known to the person skilled in the art. This type of machine takes in bagging material 130 and forms the required bags in situ for reception of the collated components prior to sealing the bags, by heat sealing or the like.

Modifications to standard machinery have been made to ensure good reliability of fill. Modifications include a packer mechanism to pull any uneven cable ties into position prior to sealing the top of the bag using sealing bars. Water injection into bag prior to sealing is optional, as is the application of a label. The cable ties fall from the collection container into the partially formed bag from above the sealing bars of the form fill machine. The form fill machine cycle includes the steps of opening the sealing bars and feeding down the bag material in tubular form to the required bag length and holding the partially formed bag in place using suction cups or the like. At the same time, the collated number of parts are fed into the partially formed bag. The packer mechanism then closes above the sealing bar and pulls down any cable ties that are inside the bag contents area. The six axis robot 130 then shakes the pre-formed bag to settle any misplaced cable ties to the bottom of the bag.

The six axis robot then moves the gripper in closer and a foam pad on the six axis gripper is pressed against the side of the bag to expel any excess air in the bag. Suction cups on the gripper grip the bag in opposition to the suction cups on the on the machine 86. The bagging machine then seals the bag and cuts the bag above the seal. A Euro-slot option is also available. The six axis gripper then pulls the bag away from the bagging machine suction cups in order to check correct sealing of the bag prior to release of the bag. The bag of cable ties can then be weight checked and placed in containers 132 supplied by the box feed mechanism 90.